Connection structure for different kinds of metal tubes

Abstract

A structure connecting dissimilar metal tubes is a bellows tube and a metal tube made of stainless steel and aluminum respectively. The bellows tube has a reinforcement portion on its outer surface. The structure includes a nipple, the reinforcement portion, and a crimp collar fitted in that order to the outside of a straight tube portion of the bellows tube. The nipple is joined to the reinforcement portion and the metal tube. A sleeve is joined to the metal tube and the crimp collar. The nipple is bonded to the inner surface of the metal tube with a resin. End faces of the reinforcement portion and the crimp collar are in contact with or located close to an end face of the metal tube.

1. A connection structure for connecting dissimilar metal tubes, comprising:
 a metal bellows tube having a reinforcement portion disposed on an outer surface of bellows of the metal bellows tube, and 
 a metal tube composed of a material different from that of the metal bellows tube, the metal bellows tube being integrally connected to the metal tube, 
 wherein a connection section on a metal bellows tube side includes
 a straight tube portion of the metal bellows tube, 
 a nipple, 
 the reinforcement portion, and 
 a crimp collar, being fitted and secured to each other in that order from an inside of the tube, 
 
 the nipple having a base joined to the reinforcement portion and a connection end extending to a metal tube side farther than an end face of the crimp collar, and 
 the crimp collar having a smaller-diameter portion extending to the metal tube side and a larger-diameter portion located on the metal bellows tube side of the metal bellows tube, the smaller-diameter portion of the crimp collar being continuous with the larger-diameter portion of the crimp collar, and 
 wherein a connection section on the metal tube side includes
 a connection end of the metal tube and 
 a sleeve secured to an outer side of the connection end of the metal tube, 
 
 the sleeve having a base joined to the connection end of the metal tube and a fitting end extending to the metal bellows tube side, and 
 the fitting end of the sleeve extending to the metal bellows tube side being externally fitted on the smaller-diameter portion of the crimp collar extending to the metal tube side, and an outer surface of a connection end of the nipple being bonded and fixed to an inner surface of the connection end of the metal tube with a thermosetting resin while an end face of the reinforcement portion of the metal bellows tube and the end face of the crimp collar are in contact with or close to an end face of the connection end of the metal tube, and wherein the larger-diameter portion is larger than the smaller-diameter portion. 
 
   
   
     2. The connection structure for connecting the dissimilar metal tubes according to  claim 1 , wherein the metal bellows tube is a stainless-steel bellows tube, and the metal tube is an aluminum tube. 
   
   
     3. The connection structure for connecting the dissimilar metal tubes according to  claim 1 , wherein the fitting end of the sleeve and the smaller-diameter portion of the crimp collar are not secured to each other by an external force. 
   
   
     4. The connection structure for connecting the dissimilar metal tubes according to  claim 3 , wherein the metal bellows tube is a stainless-steel bellows tube, and the metal tube is an aluminum tube. 
   
   
     5. The connection structure for connecting the dissimilar metal tubes according to  claim 1 , wherein the base of the sleeve is secured to the connection end of the metal tube by crimping. 
   
   
     6. The connection structure for connecting the dissimilar metal tubes according to  claim 5 , wherein the fitting end of the sleeve and the smaller-diameter portion of the crimp collar are not secured to each other by an external force. 
   
   
     7. The connection structure for connecting the dissimilar metal tubes according to  claim 5 , wherein the metal bellows tube is a stainless-steel bellows tube, and the metal tube is an aluminum tube.